1. Field of the Invention
The present invention relates to a battery pack. More particularly, the present invention relates to a battery pack incorporated into an electronic apparatus, for example.
2. Description of the Related Art
In recent years, portable electronic apparatuses such as laptop PCs (Personal Computers), cell phones, and PDAs (Personal Digital Assistants) have been prevalent, and as power sources thereof, lithium-ion secondary batteries that have advantages in high voltage, high energy density, and lightweight have been used.
The lithium-ion secondary batteries are widely used as a battery pack that is formed by adding a circuit such as a protection circuit to a battery cell in which a positive electrode, a negative electrode, and a separator and an electrolyte arranged between the positive electrode and the negative electrode are covered with a laminate film.
The battery pack is broadly classified into a so-called hard pack type and soft pack type. In a battery pack of the hard pack type, a battery cell and components including a circuit board are accommodated in a plastic case, for example, and a terminal-shaped output is provided, for example. The battery pack of the hard pack type is used for a laptop PC, for example (see Japanese Patent Application Laid-open No. 2003-045492).
A battery pack of the soft pack type is incorporated into an electronic apparatus. In the battery pack of the soft pack type, a battery cell, a protection circuit, and the like are fixed by an insulating tape or the like, a part of the battery cell is exposed, and an output such as a lead with connector connected to an electronic apparatus main body is provided.
A structural example of the battery pack of the soft pack type in related art will be described. FIG. 14 is an exploded perspective view showing a structural example of the battery pack of the soft pack type in related art. As shown in FIG. 14, in the battery pack, a positive electrode lead 118a and a negative electrode lead 118b that are drawn out from a battery cell 111, and a circuit board 112 are connected to each other via tabs 114.
A lead with connector 115 for output is connected to the circuit board 112. The battery cell 111, the positive electrode lead 118a, the negative electrode lead 118b, and the circuit board 112 are fixed by attaching insulating tapes 116a to 116d at predetermined positions.
Further, the insulating tapes 116a to 116d are double-sided adhesive tapes, with which the battery pack is fixed to a predetermined position of the electronic apparatus main body. An exterior label 117 is attached to a predetermined position of the battery cell 111. On the exterior label 117, a rating of the battery cell 111 and the like are printed and displayed.